3356-94-3

16880-46-9

3356-94-3

General procedure for the synthesis of ethyl 5-chloro-3-methyl-3-isoazole-4-carboxylate from compound (CAS:16880-46-9): to compound 139a (3 g, 17.5 mmol) was added trichlorophosphorus (POCl3, 21.5 g, 140.2 mmol, 13 ml) in a single step. Theophylline (1.8 g, 17.5 mmol) was subsequently added. The reaction mixture was stirred at 110 °C for 24 h under the protection of nitrogen (N2). After completion of the reaction, ice water (15 ml) was added to the mixture to quench the reaction and the aqueous phase was extracted with ethyl acetate (EtOAc, 25 ml x 3). The organic layers were combined, washed with saturated brine, dried over anhydrous sodium sulfate (Na2SO4), and concentrated under reduced pressure to give the intermediate compound 139b (brown oil, 2.6 g, 13.7 mmol, yield: 78.2%).1H NMR (400 MHz, CDCl3) δ 4.36 (q, J = 7.1 Hz, 2H), 2.48 (s, 3H). 1.38 (t, J = 7.2Hz, 3H).